And then we add new markup to indicate where the fold is? Something like {{*fold}} ? (It would be nice to avoid adding a whole new category of markup besides []s and {}s.)

It should not be new markup, it should use standard html/css functionality. What does tinyMCE put in for a break?

I'm thinking that within the 'content' which would have some wrappers, but not in the :core view, you would need to add some wrapping <div class="above-fold"> .... </div> <div class=below-fold"> ... </div> to mark the divisions. I think that is more in line with typical web design practice, but you could also add classes to a tag like <br class="fold"> to avoid adding element nesting, and then it is just a standard break unless the JS and CSS implement it differently.

Note that a design like this doesn't have to fetch any new data from the server, the javascript can just change the styles so the below-fold divs are hidden or not.

Also, shouldn't we be thinking in terms of having the javascript be able to just change views between say: line, folded, open (or full maybe). That suggests that this isn't really something for the :core view, but for the wrapped views (:content and :open), right? I think there may be some design tradeoffs we want to explore before we decide on how best to do this.

By new markup I meant Wagn markup, not HTML markup. How does a user indicate where the fold goes? Definitely don't want them to have to edit the HTML, and even if we provide a button in the tinyMCE toolbar I think it should add something in the edit box (as I'm assuming our link/inclusion editor will, adding [[]] {{}} markup).

I know you meant Wagn markup, and this doesn't seem like a case for that. Yes, it would need to be added somehow to tinyMCE so that they don't have to go to the HTML editor, but Wagn markup seems totally inappropriate to this case.

As far as I know, this would be a new thing for us to have something that you can enter via GUI that lacks visible markup, it seems very un-wiki to me. What if the fold weren't new markup, but just an inclusion of a new built-in card - say, *fold - that had the relevant HTML in it?

Oh duh, there also needs to be an opening div at the very beginning and a closer at the end. I guess the code could add those to any card that has *fold in it?

also see blogging blueprint